These NT style carbs are very simplistic, even crude. There is little that can be adjusted. Changing your fuel mix and needle setting is about all you need to do to get it in tune. Hold off on jetting until you are sure everything else is right (fuel, compression, ignition). Intake air leaks are something to be concerned about, especially after removing and adjusting the carb several times. Be sure there is an O ring in the throat of the carb to seal against the end of the intake. Make sure the carb is pressed snugly against the intake when tightening the clamp. Do not over tighten the clamp. The clamp does not seal the carb to the intake, the O ring seals the carb to the intake. The clamp just holds it firmly in place.